To align the text in a row to the right, you would use CSS code. Using HTML code (which is e.g. generated in the “Erweiterter Editor” is not possible here, unfortunately).
Please try adding something like this to the “Custom CSS” (Zusatz-CSS) textarea on the “Plugin Options” screen of TablePress:

.tablepress-is-123 .row-4 td {
text-align: right;
}

In that code, adjust the table ID (here: 123) and the row number (here: 4) as necessary.